Metal frame stencil



" April 22, 1941.

H. P. ELLIOTT 2,239,353

METAL FRAME STENCIL Filed April 2, 1.940

INVENT OR. firma/7 P. f//ofl A RNEY.

Patented Apr. 22, 1941 f UNITED STATES PATENT GFFICE METAL FRAME STENCIL Application April 2, 1940, VSerial No. 327,423

(Cl. 10i-127) Claims.

Vrlhis invention relates to stencils of the general type employed for fmachine printing a succession of rdi'iierent addresses and/or other matter, to meet the mailing list requirements of business of various kinds.

An object of the invention is to produce stencils of such reduced frame thickness as to stack in less than one-'third the space ordinarily occupied by the well known fibre frame stencils in common use. This results, among other advantages, in materially increasing the carrying capacity of the containing les and brings Within reach, for the convenience of the clerical force, more than three times the number of stencils in each iile.

A further object is to give stencils increased strength and durability to withstand machine action and rough or careless handling, to which they are ordinarily subjected in use.

To accomplish the above and other objects, I construct the stencil frame of thin sheet metal, to which the stencil tissue is adhesively attached.

To stiften the sheet metal frame against transverse bending, the longer edges thereof are folded o-ver upon themselves and the increased thickness thus provided limits contact between the stencil frames to the extreme edges only and serves to separate and space the panels apart when the stencils are in the les or stacked in the machine magazine. stencils are readily fed one at a time from the bottom of the stack by machine action, in the usual manner.

This edge to edge contact relation between the stencils reduces friction in the feed from the magazine and, in like manner, aids in the free movement of the stencils in the guides or runway by which they are carried through the machine.

To meet the requirements of stencil use, the metal of the frame must be flexible to readily conform to the curvature of the cylindrical platen of the typewriter and resilient, to spring back into normal flat form, when removed from the typewriting machine or bent in careless handling.

In addition, the metal must possess the peculiar quality of permitting short, sharp bends and become permanently set without cracking or breaking when bent beyond its elasticlimit, in order that the longer edges of the stencil frame may be closely folded over upon themselves, for the purposes above stated.

The only metal I have found that meets the above stated and other requirements of stencil use is cold rolled steel of about ten thousandths 'I'hus separated, the

of an inch thickness, which, however, must be processed to produce on the .surface of the steel agbasic iron phosphate before a satisfactory cement bond that is strong and lasting can `be established between the metal and the stencil tissue.

The metal is processed in an acid solution containing zinc phosphate, until a surface coating'of zinc and iron phosphates is formed. In thus processing .the metal, a double purpose is served in providing the rrequired bonding surface and in rust-proofing the metal against subsequent oxidation.

'I'he adhesive that gives the most satisfactory results in attaching the stencil tissue to the metal frame, is an emulsion containing latex and a tacky resin in dispersed phases, but other available adhesives may be employed if preferred.

To meet clerical demand for le convenience in checking or selecting stencils by the names of the addresses, without removing them from the nies, I und that by typing the name on the metalbaeked tissue, above the stencil panel in the space that is available below the turned over edge of the frame, it will appear clearly legible for quick marginal reading and save the time and necessity of reading the address panel, which could only be done by removing the stencils from the files.

A stencil construction suitable for carrying the invention into effect is illustrated in the accompanying drawing, in which Fig. 1 shows a face view of a stencil unit, and

Fig. 2 is a cross sectional view on the line 2-2 of Fig. 1, enlarged and exaggerated beyond true proportion for clearness of illustration.

Referring to the drawing, the stencil shown is a type ordinarily employed in machine-printing a succession of different addresses and is used here for illustrative purposes only and not in intended limitation of the invention, which may be applied with equal advantage to stencils of other Well known or suitable forms.

As shown, the stencil is a two layer laminated structure, one layer being a thin sheet metal frame I, of cold rolled steel, and the other a covering sheet of the usual stencil tissue 2, adhesively attached to the frame.

To strengthen and give the adhesive bond practical permanency, the metal is processed, as previously described, until a surface coating of zincv and-iron phosphates is formed thereon. 'I'he coating thus obtained, in addition to providing the required bonding surface, serves also to rustproof the metal.

The adhesive that gives the best results is the above described emulsion containing latex and a tacky resin in dispersed phases.

In the type of stencil shown, the frame is rectangular and is cut out to provide the usual window 3, within which appears the name and address that is stencilled on the attached sheet or tissue. The longer edges of the frame are folded over upon themselves, as indicated at 4, 4, to stiflen the frame and prevent transverse binding.

In the space 5, above the stencil panel and below the turned-over top edge of the frame, the name appearing in the panel address .is duplicated for convenient marginal reading, in checking or selecting stencils, without removing them from the files. Such typing, if done directly upon,

the metal, would not be readable, but upon the tissue covered surface it is clearly legible and lasting and is not only a great convenience but avoids considerable wear and tear on the stencils which would result from handling the same out- -side of vthe files.

. being processed to produce a surface formation to which the adhesive bonds the stencilizable sheet with practical permanency.

2. A two sheet laminated stencil structure, as defined in claim 1, in which the flexible resilient sheet is bendable beyond the elastic limits of the metal without cracking or breaking.

3. A two sheet laminated stencil structure, as defined in claim 1, in which the flexible resilient sheet is folded over upon itself forming a double thickness along its two longer edges to strengthen and stilien the same to resist bending of the stencil otherwise than substantially parallel to said edges.

4. As a new article of manufacture, a two sheet laminated stencil structure in which one sheet is windowed and composed of metal and the other sheet is of stencilizable material adhesively secured and permanently bonded to the metal sheet as a covering for the window therein, the metal backed upper marginal portion of the stencilizable sheet providing a surface suitable for having identification markings legibly typed thereon.

5. A two sheet laminated stencil structure," as defined in claim 4, in which the stencilizable sheet is stenciled tissue and the identification marking thereon is typed along the edge cemented to the metal frame.

HARMON P. ELLIOTT. 

